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|
require 'socket'
require 'rubygems'
require 'net/ssh/proxy/errors'
require 'net/ssh/ruby_compat'
module Net
module SSH
module Proxy
# An implementation of a command proxy. To use it, instantiate it,
# then pass the instantiated object via the :proxy key to
# Net::SSH.start:
#
# require 'net/ssh/proxy/command'
#
# proxy = Net::SSH::Proxy::Command.new('ssh relay nc %h %p')
# Net::SSH.start('host', 'user', :proxy => proxy) do |ssh|
# ...
# end
class Command
# The command line template
attr_reader :command_line_template
# The command line for the session
attr_reader :command_line
# Timeout in seconds in open, defaults to 60
attr_accessor :timeout
# Create a new socket factory that tunnels via a command executed
# with the user's shell, which is composed from the given command
# template. In the command template, `%h' will be substituted by
# the host name to connect and `%p' by the port.
def initialize(command_line_template)
@command_line_template = command_line_template
@command_line = nil
@timeout = 60
end
# Return a new socket connected to the given host and port via the
# proxy that was requested when the socket factory was instantiated.
def open(host, port, connection_options = nil)
command_line = @command_line_template.gsub(/%(.)/) {
case $1
when 'h'
host
when 'p'
port.to_s
when 'r'
remote_user = connection_options && connection_options[:remote_user]
if remote_user
remote_user
else
raise ArgumentError, "remote user name not available"
end
when '%'
'%'
else
raise ArgumentError, "unknown key: #{$1}"
end
}
begin
io = IO.popen(command_line, "r+")
begin
if result = IO.select([io], nil, [io], @timeout)
if result.last.any? || io.eof?
raise "command failed"
end
else
raise "command timed out"
end
rescue StandardError
close_on_error(io)
raise
end
rescue StandardError => e
raise ConnectError, "#{e}: #{command_line}"
end
@command_line = command_line
if Gem.win_platform?
# read_nonblock and write_nonblock are not available on Windows
# pipe. Use sysread and syswrite as a replacement works.
def io.send(data, flag)
syswrite(data)
end
def io.recv(size)
sysread(size)
end
else
def io.send(data, flag)
begin
result = write_nonblock(data)
rescue IO::WaitWritable, Errno::EINTR
IO.select(nil, [self])
retry
end
result
end
def io.recv(size)
begin
result = read_nonblock(size)
rescue IO::WaitReadable, Errno::EINTR
timeout_in_seconds = 20
if IO.select([self], nil, [self], timeout_in_seconds) == nil
raise "Unexpected spurious read wakeup"
end
retry
end
result
end
end
io
end
def close_on_error(io)
Process.kill('TERM', io.pid)
Thread.new { io.close }
end
end
end
end
end
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